// Prepare metadata indexed by spatial_dim for computing pad_before
      // and pad_after.
      int64_t input_size = input_shape[spatial_dim];
      if (input_size == ShapedType::kDynamic) return failure();
      int64_t output_size = out_backprop_ty.getDimSize(spatial_dim);
      if (output_size == ShapedType::kDynamic) return failure();
      int64_t filter_size = filter_ty.getDimSize(i);